Megan McArdle points out some reasons to buy a home--such as avoiding costs to moving and having the freedom to customize your space--but she forget a key issue: avoiding horrible landlords. While buying a house comes with the risk of getting a lemon, landlords can be the same way. They can be behind on repairs, rude, or lax on the law (which can cause many problems for you later). In one place I lived, a surprise investigation revealed that one of the rooms was not legally occupied since it lacked the proper amount of window space. A huge headache followed, eventually resulting in the occupant leaving the house.
There's something to be said for removing another person from the upkeep equation. While you lose the chance of professional specialization, you also remove the possibility of negligence which often accompanies a new (or even experienced) landlord. Many of these problems go away when you own your own home (sure, the plumbing still needs fixed, but now you're depending on the plumber instead of depending on the landlord who's depending on the plumber).